Cardiac resynchronization therapy (CRT) is a treatment for heart failure patients in which one or more heart chambers are electrically stimulated (paced) to restore or improve heart chamber synchrony. Improved heart chamber synchrony is expected to improve hemodynamic performance of the heart, such as measured by ventricular pressure and the rate of change in ventricular pressure or other measures. Achieving a positive clinical benefit from CRT is dependent on several therapy control parameters such as the atrioventricular (AV) delay and the ventricular-ventricular (VV) delay. The AV delay controls the timing of ventricular pacing pulses relative to an atrial depolarization, intrinsic or paced. The ventricular-ventricular (VV) delay controls the timing of a pacing pulse in one ventricle relative to a paced or intrinsic sensed event in the other ventricle.
Numerous methods for selecting optimal AV and VV delays for use in controlling CRT pacing pulses have been proposed. For example, clinicians may select an optimal AV or VV delay using Doppler echocardiography. Such clinical techniques are time-consuming and require an expert technician to perform. A need remains for automated methods which can be implemented in the CRT device for performing measurements correlated to the hemodynamic function of the heart and identifying optimal CRT control parameters.